Traditional star trackers are high-performance imaging instruments that contain the optical and processing elements typically found in camera systems, such as an imaging sensor focal plane and a telescope. For far-field imaging, the diffraction equation establishes a direct relationship between maximum object angular resolution (and thus imaging performance) and the diameter of the optical aperture. Accordingly, the telescope of a star tracker must generally have a fairly large aperture diameter in order to collect a sufficient amount of starlight to achieve reasonable imaging performance. As a result, the focal length (and physical length) of the telescope must be substantial as well. Thus, traditional star trackers are typically large in size, and bulky.